Hi All…Newbie here. Looking for a big HP coach. I test drove a couple today and need help.

[BrokeDude]

I drove a 45’ 2008 Monaco Signature Cambridge and a 2009 45’ Foretravel both with the 600hp Cummings motors, both were tag axle and the Foretravel was MUCH faster…Seemed to have a bunch more torque. The power difference was extreme and very noticeable throughout the rpm range. Could there have been something wrong with the Monaco…there was no check engine light on. Could the motors be that much different?
Thanks in advance for any help! I’m looking forward to contributing here as I learn more.

 

[Larry N.]

Welcome to the forums.

Do you know the weights of both coaches? Some 45' coaches might weigh close to 50,000 lbs, and some might be closer to 35,000 or so. Gearing also might be different between the two. Of course with coaches approaching 20 years old (even with younger coaches) maintenance could also be a factor. This is assuming you were on similar terrain, since climbs and descents also change apparent power. Tire pressure is another possible factor.

You might note that fuel mileage on a rig like that might be at or below 5 mpg. The 2007 45' Beaver I had, with a CAT C-13 (525 HP) and the Allison 4000 transmission, at 42,000 lbs empty, 50,000 max, sometimes got up around 6 mpg, but winds and terrain, even traffic, could affect that, and 5 to 5.5 was more common. My 2016 38' Newmar Ventana with a 360 HP engine and a 36,000 lb. max was peppier than the Beaver, including climbing steep grades with a Jeep in tow (same Jeep Wrangler on both), in addition to a lot better mileage (8.5 to 10).

Of course others likely have additional thoughts.

 

[John From Detroit]

Differences in weight. Transmission and axel will all affect performance.. Also yes they do make improvements on the engine from time to time.. I'm not that great with D's but with Gasoline engines I know they are getting smaller and peppier all the time.

 

[TheBar]

I'm not sure someone who calls themselves BrokeDude can afford to feed a huge diesel coach. Very high fuel and maintenance costs. Just an oil change is hundreds of dollars and new tires cost several thousand of dollars.

 

[BrokeDude]

Welcome to the forums.

Do you know the weights of both coaches? Some 45' coaches might weigh close to 50,000 lbs, and some might be closer to 35,000 or so. Gearing also might be different between the two. Of course with coaches approaching 20 years old (even with younger coaches) maintenance could also be a factor. This is assuming you were on similar terrain, since climbs and descents also change apparent power. Tire pressure is another possible factor.

You might note that fuel mileage on a rig like that might be at or below 5 mpg. The 2007 45' Beaver I had, with a CAT C-13 (525 HP) and the Allison 4000 transmission, at 42,000 lbs empty, 50,000 max, sometimes got up around 6 mpg, but winds and terrain, even traffic, could affect that, and 5 to 5.5 was more common. My 2016 38' Newmar Ventana with a 360 HP engine and a 36,000 lb. max was peppier than the Beaver, including climbing steep grades with a Jeep in tow (same Jeep Wrangler on both), in addition to a lot better mileage (8.5 to 10).

Of course others likely have additional thoughts.

Hey Larry…thanks for the help.
One coach is at a dealership while the other is at a private party so while I wasn’t able to drive the same route I did replicate the routes…Hilly terrain and highway.

I’ll spend some time today spec’ing them both out to maybe confirm weight or gearing as a factor.
Honestly, the difference in power was so big I have a real hard time believing the Monaco is running right, it’s almost like the turbo wasn’t working…I wish I would have looked for/at a boost gauge while driving it. Unfortunately, I drove the Monaco first and I just assumed all these big tag axle coaches must all drive that way. For more context; the Monaco was so slow to get going when I was at a stop light and got a green I was actually worried about making it across the intersection before the light turned yellow or red whereas the Foretravel was very impressive it made me wonder how something so big and heavy could accelerate like it did.

Differences in weight. Transmission and axel will all affect performance.. Also yes they do make improvements on the engine from time to time.. I'm not that great with D's but with Gasoline engines I know they are getting smaller and peppier all the time.

Thanks John…I’ll get to the bottom of the specs today and report back but as mentioned above the power difference was just way too big.

I'm not sure someone who calls themselves BrokeDude can afford to feed a huge diesel coach. Very high fuel and maintenance costs. Just an oil change is hundreds of dollars and new tires cost several thousand of dollars.

hahaha…I have no idea how I’m going to afford to use and maintain one, I figured I’d buy it first and worry about that minor detail later. wink

 

[bigbAZ]

I'm not sure someone who calls themselves BrokeDude can afford to feed a huge diesel coach. Very high fuel and maintenance costs. Just an oil change is hundreds of dollars and new tires cost several thousand of dollars.

Well if he's serious about being a broke dude he has to start somewhere and a big used motorhome is one of the best ways I know of!

 

[WILDEBILL308]

Well if he's serious about being a broke dude he has to start somewhere and a big used motorhome is one of the best ways I know of!

I know it is working for me.

 

[Kirk]

Honestly, the difference in power was so big I have a real hard time believing the Monaco is running right, it’s almost like the turbo wasn’t working…

It could be not only the gearing but also things like the electronics differences. If you increase the mpg for a large motorhome, that means less power so that is another factor to consider.

Since one coach is now 16 years old and the other 17 years old, condition is of critical importance. I would strongly recommend that you have which ever one you choose inspected by a certified professional pre-purchase RV inspector. They cost a lot but could prevent you from buying a money pit.

 

[Gary RV_Wizard]

I drove a 45’ 2008 Monaco Signature Cambridge and a 2009 45’ Foretravel both with the 600hp Cummings motors, both were tag axle and the Foretravel was MUCH faster…Seemed to have a bunch more torque. The power difference was extreme and very noticeable throughout the rpm range. Could there have been something wrong with the Monaco…there was no check engine light on. Could the motors be that much different?
Thanks in advance for any help! I’m looking forward to contributing here as I learn more.

Are you sure the Signature had the 600 hp Cummins? The standard was 525 and the 600 was optional. Sales people or even owners are often mistaken...

A turbo problem would be an easy explanation for a notable power difference and one that is often overlooked, since the engine still starts & runs smoothly.

 

[RRR]

One might have had been neutered the other might have been opened up some.

 

[Domo]

Of course there can be something wrong with a MH. Or, someone "chipped" the other so it now operates outside of it's intended range/shift patterns.

Sounds like you need to hire a mechanic to evaluate and actually measure and document any differences.

Some chassis have a "calibrated" accelerator through the ECM and one may be out of adjustment. But, once again, you need a mechanic, not conjecture on the forum.

 

[Arch Hoagland]

Which coach was at the dealership?

 

[BrokeDude]

It could be not only the gearing but also things like the electronics differences. If you increase the mpg for a large motorhome, that means less power so that is another factor to consider.

Since one coach is now 16 years old and the other 17 years old, condition is of critical importance. I would strongly recommend that you have which ever one you choose inspected by a certified professional pre-purchase RV inspector. They cost a lot but could prevent you from buying a money pit.

Thanks Kirk….So after digging in a little bit I find the Foretravel is powered by a 650 isx and the Monaco has the 600 isx
This is the info on the Monaco.

Are you sure the Signature had the 600 hp Cummins? The standard was 525 and the 600 was optional. Sales people or even owners are often mistaken...

A turbo problem would be an easy explanation for a notable power difference and one that is often overlooked, since the engine still starts & runs smoothly.

Hi Gary…see the image above. Monaco definitely has the 600 isx.
I’m thinking I had no turbo with the Monaco. The Foretravel was making up to 39lbs of boost under very medium load.

One might have had been neutered the other might have been opened up some.

True.

Of course there can be something wrong with a MH. Or, someone "chipped" the other so it now operates outside of it's intended range/shift patterns.

Sounds like you need to hire a mechanic to evaluate and actually measure and document any differences.

Some chassis have a "calibrated" accelerator through the ECM and one may be out of adjustment. But, once again, you need a mechanic, not conjecture on the forum.

Thanks Domo…Wouldn’t any such problems trigger a check engine code?

Which coach was at the dealership?

Hey Arch…The Monaco is at the dealership.

 

[Domo]

Thanks Kirk….So after digging in a little bit I find the Foretravel is powered by a 650 isx and the Monaco has the 600 isx
This is the info on the Monaco.
View attachment 2389474

Hi Gary…see the image above. Monaco definitely has the 600 isx.
I’m thinking I had no turbo with the Monaco. The Foretravel was making up to 39lbs of boost under very medium load.

True.

Thanks Domo…Wouldn’t any such problems trigger a check engine code?

Hey Arch…The Monaco is at the dealership.

To my knowledge, chipping or pedal not being adjusted to your desired response will not (usually) cause a check engine light as neither is exceeding the capabilities of the block/tranny. So, neither is a "problem."

 

[RayIN]

Do more checking. The Cummins ISX 650 HP version had a lot of problems back then. Look it up on irv2.com Cummins forum. Your same log-in works there too.
One member spent a total of $37,xxx out-of-pocket after Cummins paid their share. His ISX 650 grenaded 2X, both were #6 cylinder. i seem to recall it's something to do with the EGR valve.
FWIW, Cummins discontinued the 650 HP RV version for continuing problems. The 600 HP version is still going strong today, as far as I know.

 

[Utclmjmpr]

One thing is certain,, with a lot of "horses", you will have many mouths to feed..>>>Dan

 

[BrokeDude]

To my knowledge, chipping or pedal not being adjusted to your desired response will not (usually) cause a check engine light as neither is exceeding the capabilities of the block/tranny. So, neither is a "problem."

Again, the difference in performance between the two coaches is astronomical…I’d prefer to keep my 2004 Bounder over the Monaco if that’s how 45’ tag axle coaches perform.

Do more checking. The Cummins ISX 650 HP version had a lot of problems back then. Look it up on irv2.com Cummins forum. Your same log-in works there too.
One member spent a total of $37,xxx out-of-pocket after Cummins paid their share. His ISX 650 grenaded 2X, both were #6 cylinder. i seem to recall it's something to do with the EGR valve.
FWIW, Cummins discontinued the 650 HP RV version for continuing problems. The 600 HP version is still going strong today, as far as I know.

That’s good to know. It always perplexes me to think that such a reputable company like Cummings could or would add 50hp to an existing platform and ruin its functionality in the process…How does that even happen? However, the 600hp Monaco performed so terribly I’d rather not have a motorhome if that’s truly how they perform…reliability or not.

One thing is certain,, with a lot of "horses", you will have many mouths to feed..>>>Dan

I’ve had a number of boats and motorhomes over the years and it sounds silly to some but I’ve always found that more horses = greater efficiency. A motor with greater torque/hp works at a much lower RPM range.

 

[TheBar]

I’ve always found that more horses = greater efficiency. A motor with greater torque/hp works at a much lower RPM range.

Depends on how the extra torque/hp is derived. For instance when I bought a new 2010 Dodge truck I wanted a hemi until the salesman said for pulling a trailer that isn't the best choice. He showed me the power curve for the hemi vs the little 4.7 V8. The little V8 had 60 more hp and more torque at idle than the hemi, and had more power until the hemi surpassed it at 3200 rpm. Depends on the camshaft and fuel delivery. Bigger is not always better.

 

[Utclmjmpr]

CUMMINS as in Clessie Cummins,,not Cummings..>>>D

 

[BrokeDude]

Depends on how the extra torque/hp is derived. For instance when I bought a new 2010 Dodge truck I wanted a hemi until the salesman said for pulling a trailer that isn't the best choice. He showed me the power curve for the hemi vs the little 4.7 V8. The little V8 had 60 more hp and more torque at idle than the hemi, and had more power until the hemi surpassed it at 3200 rpm. Depends on the camshaft and fuel delivery. Bigger is not always better.

That’s very true